Florida growth regulators notified Collier County on Monday that they had signed off on landmark changes to the county's rural growth plan, but opponents are vowing a legal challenge. County commissioners approved new growth rules this summer in response to a 1999 order from Gov. Jeb Bush and the Cabinet that required the county to work with its citizens to come up with better environmental protections for its rural land. The rules apply to some 93,000 acres on the edge of Golden Gate Estates known as the rural fringe. Other changes, still under state review, would apply to almost 200,000...